It is highly difficult to believe that a virus could actually convert you into an alien species, certainly not in a matter of a few minutes. It's even harder to believe it could give you a full alien language capability and memories.

Great Moment :

Bakula, Keating and Park do an excellent job as the aliens.

Body Count :

The aliens kill one infected person at the start of the episode, and one of their own after he becomes infected near the end. Archer and co. beat up some of the aliens, and four of them are shot by the Enterprise crew.

Plotline

Beaming down to an alien planet, Archer Reed and Hoshi are transformed into aliens. Phlox determines that an alien race created a genetically engineered virus to convert other species into one of their own race in an attempt to prevent their extinction. Unfortunately one of the species which has suffered infection from the virus is determined to wipe it out – by killing anybody who is infected.